We analyzed the long-term results after argon laser peripheral iridotomy in 98 eyes of 54 patients with primary angle closure glaucoma. During a mean follow-up period of about five years, visual acuity, intraocular pressure, medication changes, and the need for filtration surgery or cataract surgery were used to evaluate the amount of possible damage that had resulted from laser iridotomy. Eyes treated with the argon laser did not appear to differ significantly from those of similar patients, described in other series, in which surgical iridectomy had been used as the therapy of choice. Argon laser peripheral iridotomy appears to be a laser peripheral iridotomy appears to be a safe and effective means of treating primary angle closure glaucoma.